1. Reproductive and Somatic Effort in Dogwoods

2. An organism’s typical pattern of : – Growth & Survival – Reproduction GrassesTrees fast growth quick repro slow growth delayed repro vs.

3. All organisms have limited energy; they allocate some energy to somatic effort & some to reproductive effort  somatic & reproductive effort = trade-off Components of Life History TOTAL ENERGY SOMATIC effort E for growth/survival REPRODUCTIVE effort E for reproduction

4.  HOW do dogwood trees allocate their energy to SOMATIC and REPRODUCTIVE efforts?  Examine 3 theories on life history trade-off. SOMATICREPRO LEAF budsFLOWER buds vs.

5. A single organism can have >1 phenotype Depending on environment, 1 tree can have multiple life history patterns (differences in SOMATIC and REPRO effort within one tree) Theory 1. Phenotypic plasticity

6. Trees with greater annual energy available will have greater reproduction. Theory 2. Sunlight affects reproductive effort

7. All organisms need time for development before they begin to reproduce (mature) Theory 3. Age affects reproduction

8. Field methods Groups of 4 or 5 Go to either sunny or shady site (as assigned) and survey 20 trees. 1) Record number of leaf buds and flower buds per 40 buds on each tree. If you’re in the roadside environment, you’ll do 20 on the sunny side and 20 on the shady side. Data sheet is on page 37. 2) Measure the DBH (cm) of each tree trunk.

9. Flower buds (reproductive) Leaf bud (somatic) Both

10. Bark: dark brown with squarish, scaly blocks. Young trees will be smooth and not as distinctive.

11. Examples of different numbers of bud scales Dogwood with two bud scales. Twigs are slender, green or purple.

12. Dogwood leaf scars are opposite, small, and encircle twig. Example of alternate leaf scars Opposite leaf scars Terminal bud

14. Flowers: white, four petals (spring) Fruit: bright red, in clusters (late summer, fall) Leaves: opposite, veins curved